Methods and means for cleaning and drying compressed fluid systems

ABSTRACT

We disclose methods and means for separating gaseous materials including vaporized moisture and for regenerating the gas separator or absorbent used for this purpose. We also disclose methods and means for separating a contaminant liquid from the aforementioned or other fluid systems and for regenerating the liquid separator thus employed.

[50] Field ofSearch........................................... 55/32,33, 58, 62,96-98,l60,16l, 163,185, 270, 302, 303, 316, 387-389; 210/(D,CD.)

[56] References Cited UNITED STATES PATENTS 1,493,110 5/1924 Paul M.Hankison Peters Township, Washington County; William Foster Walker,Bethel Park, Pa. 770,626 Oct. 25, 1968 Patented Mar. 23, 1971 [73]Assignee Hankison Corporation Canonsburg, Pa.

United States Patent [72] Inventors 21 AppLNo.

22 Filed 67 xxxx 2oo77 55% 55MB 5555 555 3,066,462 12/1962 Yap et a].Continuation-impart of application Ser. No. 3,147,095 9/1964 Kanuch637,860, Feb. 10, 1967, now Patent No. 3 152,377 10/1964 K f which is acontinuation-impart 3,339,350 9/1967 Simsofapplication$er-No-547,115,Mar-22, 3,347,026 10/1967 1966, nowabandoned which is a Primary Examiner-John Adee AttorneyDon J SmithABSTRACT: We disclose methods and means for separating gaseous materialsincluding vaporized moisture and for regenerating the gas separator orabsorbent used for this purpose. We also disclose methods and means forseparating a 55/33, contaminant liquid from the aforementioned or otherfluid systems and for regenerating the liquid separator thus em- B01d53/04 ployed.

continuation-in-part of application Ser. No. 445,639, Apr. 5, 1965, nowabandoned.

[54] METHODS AND MEANS FOR CLEANING AND DRYING COMPRESSED FLUID SYSTEMS14 Claims, 6 Drawing Figs.

55/62, 55/186, 55/191, 210/23 [51] Int.

PArEmmmzsm SHEET 1 OF FIG. 1'

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I'FIGQ4} IIINVENTORS PaalMHan/fzkozz and By Wallzlmz Fasten MzMenMETHODS AND MEANS FOR CLEANING AND DRYING COMPRESSED FLUID SYSTEMS Thepresent invention is a continuation-in-part of our copending, coassignedapplication, entitled Dryer for Compressed Fluid Systems," filed Feb.10, 1967, Ser. No. 637,860 new U.S. Pat. No. 3,464,186, which is acontinuation-in-part of our copending, coassigned application entitledDryer for Compressed Fluid Systems, filed Mar. 22, 1966, Ser. No.547,115 (now abandoned) which is a continuation-in-part of ourcopending, coassigned application entitled Air Dryer for Compressed AirSystems, filed Apr. 5, 1965, Ser. No. 445,639 (now abandoned).

The present invention relates to methods and means for separating fluidsin compressed fluid systems and more particularly to the separation ofgases including vaporized moisture and/or liquid contaminants from suchsystems. The invention is particularlyadvantageous when employed incompressed fluid systems which are subjected to gas, water vapor and/orliquid such as oil contamination. Both the gaseous and liquid separatingmeans of our invention are regenerable.

There' are many applications wherein an absorbent or other gaseous orvapor-separating means are employed in compressed fluid systems. Toprevent failure of the system and to obviate periodic replacement of theabsorbent or separating means, it is highly desirable to providea'regenerating arrangement for the absorbent or separating means. Formost applications, regeneration of the separator or absorbent must'beautomatic to prevent failure of the fluid system through human error inforgetting to replaceor to regenerate the absorbent.

in many fluid systems, a contaminating liquid .is unavoidably introducedwhich interferes drastically with the proper desorption of the absorbentor with other regenerating procedure. The contaminant liquid may beinjeqtfid in the form of microscopic mists or aerosols or largerdroplets.

Frequently, the contaminant liquid is lubricating oil or the likeunavoidably introduced into the compressed fluid system from acompressor or similar source of fluid.

In many types of gas or moisture separators the contaminating liquidbecomes coated upon the separator absorbent so as to interfere with itsgas or moisture, sorptional properties. The presence of a liquidcontaminant also prevents a proper or complete regeneration of the gasor moisture separator. Thus,

the automatic feature inherent in many cyclically regenerable systems islost, for the absorbent or separating means must be closely monitored toensure replacement when the extent of liquid contamination becomesprohibitive.

ln many applications to which our invention is well suited, the gas ormoisture absorbent is a desiccant material such as silica gel, activatedalumina, anhydrous calcium sulfate, molecular and various finely porousmaterials known as sieves. For the most part, these materials can beperiodically regenerated by reverse flushing at reduced pressureswithout the application of heat. Examples of these processes aredisclosed in the U.S. Pats. to Axt No. 3,182,435; Glass et al. No.3,080,693; and Kennedy et al. No. 2,955,673. The disadvantages of theseprocesses particularly with respect to vehicular brake'systems are setforth in our aforementioned copending application, Ser. No. 637,860.Moreover, none of these patents teach the proper regeneration of adesiccant or other absorbent in the presence of a contaminating liquidor ,the use of regenerable means for separating such liquid.

There have been many attempts to prevent a contaminating liquid fromreaching a desiccant or other absorbent or other .critical structurewhich may be damaged by such liquid. Various liquid filters or absorbershave been proposed some of which are shown in the aforementionedpatents. Other fonns of filters for contaminant liquids are disclosed inthe U.S. Pats. to Wilkerson No. 2,869,570; Dilworth No. 2,812,860;Kauer, Jr. et al. No. 3,279,l5 1; White No. 2,962,l l9; and Taylor No.3,197,946. in the White patent a sintered metal filter is used in :anattempt to remove oil from a compressed air-system. Oil

apparently clings to, both sides of the filter, which is supportedvertically and flows downwardly into collecting chambers on either sideof the filter. The filter is spring loadedagainst a valve seat, and whenthe filter becomes clogged the fluid pressure lifts the filter from theseat to bypass the filter. The White arrangement, therefore, isself-defeating.

The Wilkerson patent shows an air line trap with an automatic drainhaving an annular strainer screen in an air expansion chamber, fromwhich collected moisture drips on to a partition, and thence into a pumpchamber. The Wilkerson arrangement apparently is enabled only to removeentrained moisture droplets. In any event it would be ineffective ineliminating microscopic mists or aerosols.

The Taylor and Kauer, Jr. et al. patents merely disclose conventional indepth filters. The Taylor arrangement appears to be capable ofcoalescing only the larger droplets of moisture, while Kauer, Jr. et al.disclose a filter of pressed copper wool for preventing dust particlesfromentering and clogging an orifice plate downstream of the filter.None of the patents described thus far shows a liquid filter which isregenerable in any source of the term. Although the Kauer, Jr. et al.filter (for particulate material) is used in a cyclic system, there isno flow reversal through the conduit branch in which the filter ispositioned.

The Dilworth patent discloses an annular filter for particulate matterand positioned upstream of an orifice plate to prevent clogging of theorifice. A compressed air chamber is provided adjacent the annularfilter for periodically flushing, under control of manually operatedvalve, the particulate matter collected on the normally upstream side ofthe filter. The Dilworth filter likewise cannot remove microscopic mistsor aerosols and therefore is not logically regenerable for liquidseparation purposes. All of these liquid filters or separating meansfail to prevent ultimate passage of contaminating liquids therethroughas they become saturated with the liquids. Use of such devices isself-defeating as the devices themselves must be periodically removedfor cleaning and/or replacement. No adequate means have been proposedfor periodically regenerating a regenerable liquid separator. Inparticular, no method or apparatus has been disclosed for periodicallyregenerating both a gas or moisture separator and a liquid contaminantseparator used to prevent significant concentration of liquidcontaminants within the gas or moisture separator.

As noted previously, our invention is amenable to a diversity ofapplications. For example, in many applications such as in gaseousdiffusion separators, the separators are capable of operatingindefinitely, if adequate means are utilized to prevent contact with acontaminant liquid. In addition to applications as set forth in ourcopending application Ser. No. 637,860, in gas diffusion systems andvehicular brakes, our invention is useful in a wide variety ofapplications such aspaint spraying units, communication line purgesystems, and in a large variety of commercial and laboratoryapplications involving the separation or absorption of eithercondensable or noncondensable gases. In these applications, the gas ormoisture separator or absorbent is subject to contamination by variousliquids unavoidably or inadvertently introduced into the system.

As set forth in our aforementioned application Ser. No. 637,860 ourinvention is particularly useful in air brake systems for vehicles, asthese systems are subject to both moisture and oil contamination. Thedesirability of providing moisture free air for such systems to preventclogging or corroding of the system and freezing during inclementweather has long been recognized and is elaborated upon in detail in.our copending application Ser. No. 637,860. The advantages of aregenerable liquid separator for compressed air systems is likewise setforth in our last-mentioned application in considerable detail. Inbrief, oil or other contaminating liquid is unavoidablyintroduced intothe compressed air or other fluid system by the compressor. Despite thepresence of conventional filters, the oil or other contaminant liquidquickly permeates the desiccant or other absorbent and its sorptioncapacity is rapidly reduced below an acceptable level. Moreover,conventional desiccant or other absorbent regenerating procedures areinadequate to remove the liquid contaminant.

We overcome these defects of the prior art by providing a gas ormoisture separator which can be periodically regenerated in such mannerthat at least the larger droplets of liquid contaminant are flushed outof the desiccant or other absorber. For use with the aforementioneddesiccant or absorber or with other gas or moisture separating means, weprovide a periodically regenerable liquid separator. In one arrangementthe liquid separator is capable of coalescing a contaminating liquidwhich is then periodically removed in a unique manner. We also providemeans and methods of regenerating gas and liquid separators at the sametime and/or in tandem.

The liquid separator of our invention can be employed in many types offluid systems (with or without gas or moisture separating means) whereinthe flow is periodically reversed at reduced pressures or at otherwisediffering flow rates. Our invention comprises a unique coalescer formicroscopic mists, aerosols or larger droplets, and for periodicregeneration in a cyclically reversible fluid system. In a variation ofour liquid separating means, two or more liquid separators are spacedtandemly for stagewise liquid separation but for substantiallysimultaneous regeneration. The latter arrangement, the normallydownstream separator or separators can be provided with progressivelyfiner coalescing media.

We accomplish these desirable results by providing a desiccant dryingsystem for use with a compressed fluid containing desiccantcontaminating liquid droplets, said system including a containerstructure for supporting a mass of desiccant material therein, aseparator for said liquid positioned within said container structure,means for spacing said separator from said desiccant material, saidseparator including a coalescing member of foraminous construction andbeing extended entirely across the flow path of said fluid through saiddesiccant, and means within said container structure for periodicallyreverse-flowing a first portion of said fluid through said separator andfor periodically reverse-flowing a second portion of said fluid throughsaid desiccant material for regenerating said separator and saiddesiccant material respectively.

We also provide a similar regenerating means wherein said liquidseparator includes a relatively thin coalescing member and a pair offoraminous backing members coextending with said coalescing member andsandwiching said coalescing member therebetween.

We also desirably provide a similar method wherein the liquid separatoris positioned horizontally, said lower volume flow is upwardly throughsaid liquid separator, said higher volume flow is downwardly throughsaid separator.

We also desirably provide a similar method wherein at least two of saidliquid separators are spacedly mounted in tandem in said system andalong said path. I

During the foregoing discussion, various objects, features andadvantages of the invention have been set forth. These and otherobjects, features and advantages of the invention together withstructural details thereof will be elaborated upon during theforthcoming description of certain presently preferred embodiments ofthe invention and presently preferred methods of practicing the same.

In the accompanying drawings we have shown certain presently preferredembodiments of the invention and have il lustrated certain presentlypreferred methods of practicing the same, wherein:

FIG. 1 is a longitudinally sectioned view of one arrangement of a dryingtower in which our improved method is used to advantage;

FIG. 2 is a longitudinally sectioned view of another arrangement of ournovel drying tower and illustrating still other methods for cleaning andregenerating certain components thereof; FIG. 2 is taken generally alongreference line II-II of FIG. 3;

FIG. 3 is a top plan view of the apparatus shown in FIG. 2;

FIG. 4 is a cross-sectional view of the apparatus as shown in FIG. 2 andtaken along reference line IV-IV thereof;

FIG. 5 is another cross-sectional view of the apparatus as shown in FIG.2 and taken along reference line V-V thereof; and

FIG. 6 is a partial, longitudinally sectioned view illustrating otherforms of liquid separating means, and methods for cleaning the same.

Referring now to FIG. 1 of the drawings, our novel drying and/orcleaning method is set forth in connection with drying tower 15. Thedrying tower 15 is provided with inlet, outlet and dump valvearrangements, with means also for imparting a swirl to the incoming anddumped air flowing through the tower for the purpose of removingsuspended oil droplets or aerosols or other foreign matter from thesystem.

In the arrangement of FIG. I, then, the desiccant tower 15 includes thegenerally cylindrical container 116 having a mounting flange 118 at theupper opening thereof for securance to an apertured cover 120 having atapped outlet opening 122 therein. A sealing ring 124 is spacedlysecured to the undersurface of the cover plate 120 so as to define anoutlet plenum 126 therebetween. When thus secured, the sealing 124 isaligned with desiccant cartridge 72 when properly positioned within thecontainer 116 by means of compressed spring 73 disposed at the lower,frustoconical section 128 of the container 116.

The cartridge 72 is further positioned and centered within the outercontainer 116 by means of a spiral vane 130 secured about the outer wallsurface of the cartridge 72 and described in greater detail hereinafter.As set forth previously, the cartridge 72 can contain in the majorproportion of its volume a desiccant 21 separated from a filter material19 such as wire mesh, by means of a porous partition member 20. Thefilter material 19 thus is confined to the inlet end of the cartridge72.

When thus mounted, the cartridge is spaced inwardly from the outercontainer 116 to define an annular plenum chamber 132, whichcommunicates with the tapped inlet port 13.

The input air of the tower 15 thus flows generally downwardly throughthe annular plenum 132, but is swirled by the spiral vane 130 interposedas aforesaid between the cartridge 72, and the inner wall surface of thecontainer 116. This swirling action throws oil particles or othersuspended foreign matter in the input air against the inner wallsurfaces of the outer container 116, where it runs down to thefrustoconical collector section 128 at the bottom end of the container116. The frustoconical section 128 then conducts the extracted foreignmatter toward the central expeller or dump opening 132 of the container.Thus, when air is dumped from the tower at the initiation of itsregeneration, the sudden outrush of air through the dump opening 132 anddump valve 108 carries with it the undesirable foreign matter which isthus collected from the inner wall surfaces by the frustoconical section128.

In the embodiment of our invention, as illustrated in FIG. I, whirlingof the incoming fluid prevents at least part of the foreign mattercontaminants, such as dust, water droplets and lubricating oil dropletsfrom reaching the desiccant material. Foreign matter is deposited on theinner walls of the outer container by centrifugal forces developed bythe whirling action. As a certain quantity of water and/or oil dropletsis inevitable in any compressed fluid system, these liquids togetherwith any entrained dust or other foreign particulate matter, coalesce onthe inner wall surfaces and eventually run down to the bottom area ofthe container for removal by the dump valve.

Referring now more particularly to FIGS. 2 to 5 inclusive of thedrawings, further embodiments of our drying and cleaning methods are setforth in connection with a desiccant container 200, the outlet 202 ofwhich is coupled through conduit 204 and check valve 206 to the storagetank 28. The check valve 206 permits full flow through the conduit 204from the container 200 to the storage tank 28, but does not permit anyflow whatsoever in the reverse direction. Thus, there is no differentialflow control means between the container 200 and the storage tank 28.Therefore, no compressed fluid can be withdrawn from the storage tank 28to the container 200 at any time, as during the regenerative portion ofthe cycle for regenerating desiccant material 208 contained within thecontainer 200. The apparatus of FIGS. 2 to 5 can be employed inconjunction with vehicular brake systems without violation of applicablecodes which prohibit extracting purge or regenerative fluid from thestorage tank 28.

The desiccant container 200 is provided with an inlet 210 for connectionto a suitable compressor. The container 200 also is provided with a dumpor exhaust valve 212 similar to that shown in FIG. 1 and for the samegeneral purposes.

In this arrangement of the invention, the mass of desiccant material208, which can be one of the materials mentioned previously, iscontained within aninner shell or cartridge 214, which is positioneddesirably coaxially within the container 200 and spaced inwardlytherefrom to form an annular flow passage or plenum 216. Withthisarrangement, compressed air entering the container 200 through theinlet 210 flows downwardly through the plenum 216 as denoted by flowarrows 218 to the lower space 220 adjacent a rounded bottom 222 of thecontainer 200. The lower end of the cartridge 214 rests upon the upperreaches of the rounded bottom 222 by means of a plurality of feet 224spaced around the lower extremity of the cartridge 214, with three suchfeet 224 being utilized in this arrangement as better shown in FIG. 5.Between the feet 224, deeply chamfered areas 226 of the lower extremityof the cartridge 214 permit the compressed fluid to flow between thefeet 224 as denoted by flow arrows 228, into the bottom plenum area 220of the container 200. In this example, the rounded bottom 222 serves toposition the lower end of the cartridge 214 substantially coaxially ofthe container 200 to provide the annular flow plenum 216 with a throughjoining flanges 223 and 225 respectively. In

furtherance of this purpose, a sealing ring 227 is inserted adjace'ntthe inward junction of the flanges 223 and 225 where tightening of bolts229 compresses the sealing member 227 between the adjacent extremitiesof the container 200, its closure 221 and the upper end portion of thecartridge 214. Thus, the sealing member 227 seals the closure 221 to thecontainer 200 and at the same tirrie positions the upper end portion ofthe cartridge 214 coaxially of the container 200, while sealing theupper plenum or purge chamber 242 of the container 200 from the annularplenum 216 between the container 200 and the inner wall or cartridge214.

From the plenum 220 the compressed fluid flows upwardly through a numberof aperture means 230 in oil separator 232, as indicated by flow arrows231, and through lower filter pad 234 and thence through the desiccantmaterial 208. From the desiccant material 208 the compressed fluid flowsupwardly through upper filter member 236 through an intermediate plenum238 and thence through a central aperture 246 in domed baffle 240 intoan upper plenum 242. From the upper plenum 242 the compressed fluidexists from the container 200 as denoted by flow arrows 244 throughoutlet 202, conduit 204 and check valve 206 to the storage tank 28. Aspointed out previously, once the compressed fluid is conveyed into thestorage tank 28, it cannot be extracted therefrom to the conduit 204because of check valve 206. Accordingly, no compressed fluid is returnedfrom the storage tank 28 to the container 200 for purposes ofregenerating the desiccant 208.

The compressed fluid flows through the central flow aperture 246 ofbaffle 240 as denoted by flow arrow 248. The flow of compressed fluidthrough the baffle aperture 246 is controlled by reverse bleed checkvalve 250, the valve-closing member 252 of which is provided with areverse bleed aperture 254. The check valve 250 otherwise is ofconventional design and in this arrangement the housing 256 thereover isthreaded into container 258, the lower end of which is apertured at 260arid otherwise further constricts the flow opening 246 of the domedbaffle'240. The check valve receptacle 258 in this example is secured tothe top surface of the bafi'le 240 as by welding, as viewed in FIG. 2.

In this arrangement, the flow baffle 240 desirably is domed inasmuch asa relatively high pressure differential can exist thereacross when theexhaust valve 212 is opened during the regenerative portions of theoperating cycle. Thus, the intermediate plenum 238 at such times,together with the desiccant chamber 208, is exhausted within a veryshort time. The rapid flow of decompressed fluid from the intermediateplenum 238 flushes dirt and other foreign matter from the desiccant 208and also from the separator 232. The intermediate plenum fluid also aidsin regenerating the separator 232 in the manner described below.

On the other hand, the upper plenum 242 which serves as an integralpurge chamber for the desiccant material 208, is exhausted at a muchslower rate owing the the differential flow control feature of thereverse bleed check valve 250. Therefore, within a very short time afteropening the exhaust valve 212 substantially the entire compressor outletpressure will exist across the domed baffle 240.

The volume of dry compressed fluid normally contained within the upperplenum 242 at the. end of the compression cycle is sufficient, afterbleedingslowly through aperture 254 of the reverse metering check valve250 and expanded to substantially atmospheric pressure within thedesiccant chamber 208 by exhaust valve 212, to completelyregenerate theabsorbent material or desiccant 208.

The upper filter member 236 in this example is slidably mounted withinthe upper end portion of the cartridge 214 and adjacent the domed flowbaffle 240. In a desirable form of the upper filter member 236, a porousfiltering pad 262 such as open-celled polyurethane foam is likewisestretched over an apertured, relatively rigid backing member 264, havinga somewhat smaller diameter than the inner diameter of the cartridgeshell 214. The filter pad 262 is partially wrapped about the peripheryof the backup plate 264 so that the filter member 236 is closely andslidably fitted within the shell 214. The backup plate 264 can beconstructed from perforated sheet steel or other suitably foraminousstructural material.

Desirably, the central region of the backup plate 264 is not aperturedwhere it engages retaining cup 266 for suitable biasing means such asspring 268. The biasing means 268 urges the slidably mounted upperfilter pad 236 downwardly against the desiccant material 208 to applycompression thereto. This compressive action minimizes vibration andattrition of individual desiccant particles that may be provided withinthe desiccant chamber.

The lower filter pad 234 is similarly constructed with the exceptionthat the lower backup plate 270 can be uniformly per forated as shownand is provided with a depending lip 272 whereby the backup plate andthe filter material 274 stretched thereover is positioned in thecartridge shell 214 with rivets 276 or other suitable fastening means.

Spring-retaining cup 266 can be omitted if desired whereupon the lowerend of the spring 268 can engage directly the upper surface of the upperbackup plate 264. Use of the spring retaining cup 266, however, servesas a catch basin for any particles of foreign matter which may issuethrough the reverse bleed check valve 250 during desiccant regenerationwhen purge flow fluid flows from the purge chamber 242 through theintermediate plenum 238 and thence through the desiccant chamber 208 asdenoted by reverse flow arrows 278.

The cup 266 as shown in FIG. 2 is mounted directly beneath the centralflow aperture 246 of the domed baffle 240. The reversed regeneratingflow from the purge chamber 242 through the check valve aperture 254 iscaused to disperse radially by the presence of the cup 266 so that aportion of the reverse flow is diverted toward the outer periphery ofthe perforated backup plate 264. As a result, the entire mass of thematerial in the desiccant chamber 208 is exposed to the reverse,regenerative flow from the purging chamber 242.

The oil separator 232, as arranged in accordance with our invention,includes exemplarily a pair-of foraminous or, as shown, backup members280 and 282 with a relatively thin disc of foraminous or porousmaterial, such as filter paper 284 sandwiched therebetween. The termforaminous as used herein and in the appended claims in inclusive ofapertures of uniform or nonuniform sizes, and of porosity such asencountered in the aforementioned filter paper or in finely or coarselysintered members, and of reasonable equivalents.

Thus, it is contemplated that a relatively thin, finely sinteredfiltering member 284 can be sandwiched between relatively thick,coarsely sintered backing members 280 and 282 to provide the necessarystructural rigidity of the separator 232. Alternatively, a single,relatively thicker but finely sintered filtering member (not shown) orother finely porous filtering member having requisite structuralstrength to withstand the anticipated pressure drops thereacross, can beemployed without one or both of the backing members 280, 282 asdescribed more fully below.

The backup members 280, 282 and the filter paper 284 are securedtogether by a clamp or channeled peripheral retaining member 286 whichis shrunk or force-fitted into the lower end portion of the cartridge214 to securely position the oil separator 282 at a location spaced fromthe lower filter pad 234. As better shown in FIGS. 2 and 5, each of thebackup plates 280, 282 are provided with a relatively large number ofapertures, with the respective apertures thereof being desirably insubstantial alignment. The imperforate areas of the backup plates 280,282 thus provide structural rigidity to the filter paper 284, whichwould otherwise rupture if substantially larger continuous areas thereofwere presented to the incoming compressed fluid (flow arrows 231) and tothe explosive discharge of the fluid in cartridge 214 during the initialstage of reactivation. The apertures 230 of the upper backup member 280of the oil separator 232 also serve to collect the oil which coalesceson the upper surface of the filter paper 284.

A space 286 between the lower filter pad and the oil separator 232prevents contact of the upper pad 234 and the desiccant material 208 bythe coalesced oil, whose capilarity and wettability otherwise wouldpermit a relatively rapid transfer of the coalesced oil from theseparator 232 to the lower filter pad 234.

In the arrangement shown, the filter paper 284 is a resin impregnatedfilter paper of commercial availability such as Liquid Separator Paper,Run 0106024 (0.030 inch thick), made by Riegel Paper Corp., PaperDivision, 260 Madison Avenue, New York, N.Y. 10016. However ordinaryfilter paper, thin porous metal sheet or sintered metal, porous plasticmaterial or porous glass can be substituted.

It is contemplated that the filtering member 284 and the backup members280 and 282, if used, need not be flat but can take any desired andconvenient shape such as conical or cup-shaped, as long as the separator232 extends entirely across the path of the incoming compressed fluidand of the outgoing exhaust or purge fluid.

Where a somewhat more rigid filter member, such as a sintered member, isused in place of the filter paper 284, the normally downstream backupmember 280 can be omitted where the pressure differentials usuallyassociated with normal, forward flow of compressed fluid (flow arrows231) are not severe. Where a sintered structural material such assintered bronze, stainless steel or carbon is employed for the filtermember comprising the separator 232, both backup members can be omitted.

Bypassing of the filter member or disc 284 is prevented by a tightlyfitted engagement between the channel retaining ring 238 and theadjacent inner wall portion of the cartridge 214.

Since in most compressed fluid systems the contaminating oil exists inthe system as a mist of microscopic dimensions, a surface-type filterwith minute pore size, such as that shown at 284 in FIGS. 2 and 5, isrequired to coalesce the oil mist. The use of a surface-type filterpermits the oil separator 232 to be periodically regenerated by highvolume flow reversals, in contrast to the use of a depth-type filter.

In order to ensure complete purging and regeneration of the oilseparator 232, the latter in this example is supported in a horizontalposition so that the coalesced oil is largely confined to the apertures230 of the upper backup plate 280 at relatively low forward flow rates.At higher forward rates the uprush of air or other incoming fluidthrough the aperture 230 tends to force the coalesced oil out of theapertures and onto the intervening solid portions of the upper plate280. At high volumetric reverse flows the coalesced oil is wiped offthese upper plate surfaces and carried back through the apertures 230and filter disc 234 as described below. In no case, however, does anysignificant quantity of coalesced oil migrate downstream to thedesiccant 208.

It is contemplated in appropriate applications and in modifiedstructures, that the oil separator 232 can be mounted in other than ahorizontal position, or that the normal flow of compressed fluid can bereversed so that coalesced oil collects on the underside of theseparator 232 and the reverse regenerating flow purges the coalesced oilupwardly through the separator instead 'of downwardly. In any event, thesurface tension of the coalesced oil is sufficient, under most operatingconditions, to maintain the coalesced oil on the normally downstreamside of the separator without drip ing. Where a perforated or otherforaminous backing member is employed on the normally downstream side ofthe separator, the edges of the perforations and the interveningsurfaces of the backing member offer additional oil-collecting surfacesirrespective of the position of the separator.

When the exhaust valve 212 is periodically opened, the almost explosiveoutrush of compressed fluid from the intermediate plenum 238, thedesiccant chamber 208, and the space 286 between the lower filter pad234 and the oil separator 232 forces the coalesced oil on-the normallydownstream sideback through the filter disc 234 and through theapertures 230 of the lower or normally upstream plate 282, and out ofthe container 200 as denoted by flow arrows 290. In the case of acompressor in proper operative condition, the volume of coalesced oil isseldom sufficient to enter the apertures of the upper backup member 280so that the coalesced oil stands upon the upper surface of the normallydownstream backup member 280, which is wetted by the coalesced oil, butthere is little or no possibility of wetting the adjacent inner wallportion of the inner shell 214. However, with poorly maintainedcompressors which pass excessive quantities of lubricant, the entireupper or normally downstream surface of the oil separator 232 can becompletely covered with coalesced oil without preventing coalescence ofadditional fine oil droplets (aerosols), and the separator can still beproperly regenerated by the high volume reverse purge flow. Thus, theseparating space 286 prevents the coalesced oil from traveling with theincoming fluid stream to the desiccant material, and the coalesced oilis substantially completely removed from the oil separator during theinitial portion of each regenerative interval.

When the aforementioned compressor has restarted or when incomingcompressed fluid is otherwise admitted to the container 200, the oilseparator is again immediately available for removing oil contaminants.

During the remainder of each regenerative interval and after the initialoutrush of compressed fluid from the chambers 238, 208 and 286,regenerative fluid, exiting through the reverse bleed aperture 254 ofthe check valve 256 continues to flow through the desiccant chamber 208until the desiccant material is regenerated, at which time thecompressing interval of the operating. cycle is reinstated.

IDIOT; H

The oil separator 232 and desiccant 208, then, essentially areregenerated in sequence. The momentary pressure drop which occurs acrossthe oil separator 232 when the dump valve 212 is opened quicklyregenerates the oil separator 232, whereupon the relatively slowerregeneration of the desiccant material 208 commences. At this timeregenerative fluid is conveyed from the upper plenum 242 through thedifferential fluid control means, including the reverse bleed checkvalve 256), and through the desiccant material as denoted by flow arrows273. This flow is substantially at the discharge pressure of the dumpvalve 212.

It will be seen that the desiccant, theoil separator means 238, the oilseparator-regenerating means including chambers 20B, 238, 286 and'thedesiccant regenerating means including the upper plenum 242 and thedesiccant purge means or chamber are all contained within a singlecontainer 200 so that the number of external plumbing connections withinthe system are minimized. The components of the compressing and dryingapparatus which are thus contained within the container 200 can bequickly and easily installed or removed as a single unit of the system.The use of the sealing ring 227 in addition to its functions describedpreviously also reduces the amount of vibrational or other shock forcestransmitted to the cartridge 214 from the outer container 200.

If desired, a number of brackets 292 can be secured to the outer wallsurface of a container 200 for mounting purposes.

Referring now to FIG. 6 of the drawings, another arrangement of theoil-separating means is illustrated therein. It will be understood, ofcourse, that the oil-separating means according to either FIG. 2 or 6can be utilized in other apparatus than that shown, as long as thesystem in which the oil separating means are utilized is subjected toperiodic flow reversals of the character which will purge the coalescedoil in the manner described. v

In the modification of FIG. 6, a pair of oil separators 294 and 296 arespacedly mounted adjacent the lower end of cartridge 214. The oilseparators 294, 296 are spaced from one another and from the lowerfilter pad (not shown in FIG. 6) or other system component with theresult'that the spaces 286 and 298 prevent oil communicationrespectively therebetween. The normally upstream oil separator 294 isgenerally similar to the upper separator 296 and both are constructedsubstantially in the manner described above in connection with the oilseparator 232 in connection with FIGS. 2 and 5. Desirably, the filterdisc 300 of the normally downstream separator 296 is provided with asmaller pore size than the lower filter disc 302. With this arrangement,the proportion of removed oil is progressively increased, although itwill be understood that the filter discs 300, 302 can be identicaldepending upon the application of the invention. If desired, additionaloi] separating means (not shown) can be mounted in a similar manner inseries with the oil separators 294, 296 and spaced therefrom and from anadjacent system component (not shown) as set forth in connection withthe lower filter pad 234 of FIG. 2.

During each flow reversal, the coalesced liquid on the normallydownstream side of the downstream separator 296 is preferred methods ofpracticing the same, it is to be distinctly understood that theinvention is not limited thereto and may be otherwise variously embodiedand practiced within the scope of the following claims.

We claim:

1. A method for periodically regenerating a relatively thin foraminousliquid separator for a liquid contaminant, said method comprising thesteps of defining a path for flow of fluid containing said contaminant,extending said separator completely across said path so that all of saidfluid flows through said separator, shaping said separator such thatsubstantially all of the liquid contaminant collected thereby coalesceson the normally downstream outer surface of said separator, flowing saidfluid and liquid contaminant in a nor mal flow direction along said pathuntil a significant quantity of said liquid contaminant coalesces onsaid separator, segregating a portion of said fluid downstream of saidseparator relative to said normal flow, periodically flowing saidsegregated portion in a reverse direction through said separator at asubstantially faster rate to drive said coalesced liquid back throughsaid separator, and conducting said segregated portion flow and thecoalesced liquid contained therein away from said fluid path.

2. The method according the claim 1 and comprising the additional stepof reverse-flowing said fluid portion to a region of substantially lowerfluid pressure. I

3. A method for periodically regenerating desiccant material and adesiccant contaminating liquid separator, said method comprising thesteps of defining a fluid path, placing said desiccant material and saidliquid separator at spaced locations along said path so as to extendcompletely across said path, flowing a moisture and contaminatingliquid-containing fluid in a normal flow direction along said path andthrough said separator and said desiccant material in that order,segregating first and second portions of said fluid normally downstreamof said desiccant and said separator, periodically flowing said firstfluid portion in a reverse direction along said path and through saiddesiccant material to regenerate the same, and periodically flowing saidsecond fluid portion in a reverse direction along said path through saidseparator to regenerate the same.

4. A method for periodically regenerating desiccant material, saidmethod comprising the steps of defining a fluid path, placing saiddesiccant material in said path, flowing a moisture and contaminatingliquid containing fluid in a normal flow direction through said path andthrough said desiccant material, segregating first and second portionsof said fluid adjacent said desiccant on a normal downstream sidethereof, periodically flowing said first fluid portion in a reversedirection along said path and through said desiccant material at afaster rate for desiccant flushing purposes, periodically flowing saidsecond fluid portion in a reverse direction along said path at a slowerflow rate through said desiccant material to regenerate the same, anddirecting each of said fluid portions radially of the adjacent surfaceof said desiccant material and thence through said desiccant material.

5. The method according to claim 3 and comprising the addriven backthrough both separators 294, 296 and out of the di i l steps ofsegregating a third portion of said fluid adsystem. The fluid portion inthe space 298 between the separators at least aids in driving thecoalesced liquid on the downstream side of the upstream separator 294back through the separator 294.

From the foregoing it will be apparent that novel and efficient meansand methods have been disclosed herein for separating fluids incompressed fluid systems. Although our novel methods have been describedprimarily for use with compressed air systems, it will be apparent thatour arrangement is readily adaptable for use with other compressed gasesor fluids Similarly, as pointed out in the opening paragraphs, oursystem is not limited to the removal of water vapor and oil from suchsystems but is much more broadly based. While we have shown anddescribed certain presently preferred embodijaccnt said desiccantmaterial, and periodically flowing said third fluid portion in a reversedirection along said path and through said desiccant material and saidliquid separator to flush foreign material from said desiccant materialand to aid in regenerating said separator.

6. The method according to claim 3 and comprising the additional step ofreverse-flowing said second portion at a substantially faster rate.

7. The method according the claim 6 and comprising the additional stepsof reverse'flowing said first and said second fluid portionsrespectively to regions of substantially reduced fluid pressures.

S. The method according the claim 3 and comprising the additional stepof segregating said first portion adjacent said ments of the inventionand have illustrated certain presently desiccant and said second portionadjacent said separator.

9. The method according to claim 1 wherein at least two relatively thinforaminous liquid separators are spacedly mounted along said path andsaid method comprises the modified step of reverse-flowing said portionin tandem through said separators so that surface coalesced liquid onthe nonnally upstream separator is driven back through said upstreamseparator and that the surface coalesced liquid on the normallydownstream separator is driven through both of said separators.

10. The method according to claim 9 and comprising the additional stepsof segregating a second fluid portion in a space between saidseparators, and periodically reverse-flowing said second portion throughsaid upstream separator to aid at least partially in regenerating thesame.

11. A desiccant drying system for use with a compressed fluid containingdesiccant contaminating liquid droplets, said system including acontainer structure for supporting a mass of desiccant material therein,a separator for said liquid positioned within said container structure,means for spacing said separator in a normally upstream direction fromsaid desiccant material, said separator including a coalescing member ofthin foraminous construction and being extended entirely across the flowpath of said fluid through said desiccant, said member being shaped toretainv substantially all of the coalesced liquid on the normallydownstream surface thereof, and means coupled to said containerstructure for periodically reverse-flowing a first portion of said fluidthrough said separator and for periodically reverse-flowing a secondportion of said fluid through said desiccant material for regeneratingsaid separator and said desiccant material respectively.

12. The combination according to claim 11 wherein said liquid separatorincludes a relatively thin coalescing member and a pair of foraminousbacking members coextending with said coalescing member and sandwichingsaid coalescing member therebetween.

13. The combination according to claim 12 wherein the liquid separatoris positioned horizontally, said lower volume flow is upwardly throughsaid liquid separator. said higher volume flow is downwardly throughsaid separator.

14. The combination according to claim 11 wherein at least two of saidliquid separators are spacedly mounted in tandem in said system andalong said path.

2. The method according the claim 1 and comprising the additional stepof reverse-flowing said fluid portion to a region of substantially lowerfluid pressure.
 3. A method for periodically regenerating desiccantmaterial and a desiccant contaminating liquid separator, said methodcomprising the steps of defining a fluid path, placing said desiccantmaterial and said liquid separator at spaced locations along said pathso as to extend completely across said path, flowing a moisture andcontaminating liquid-containing fluid in a normal flow direction alongsaid path and through said separator and said desiccant material in thatorder, segregating first and second portions of said fluid normallydownstream of said desiccant and said separator, periodically flowingsaid first fluid portion in a reverse direction along said path andthrough said desiccant material to regenerate the same, and periodicallyflowing said second fluid portion in a reverse direction along said paththrough said separator to regenerate the same.
 4. A method forperiodically regenerating desiccant material, said method comprising thesteps of defining a fluid path, placing said desiccant material in saidpath, flowing a moisture and contaminating liquid containing fluid in anormal flow direction through said path and through said desiccantmaterial, segregating first and second portions of said fluid adjacentsaid desiccant on a normal downstream side thereof, periodically flowingsaid first fluid portion in a reverse direction along said path andthrough said desiccant material at a faster rate for desiccant flushingpurposes, periodically flowing said second fluid portion in a reversedirection along said path at a slower flow rate through said desiccantmaterial to regenerate the same, and directing each of said fluidportions radially of the adjacent surface of said desiccant material andthence through said desiccant material.
 5. The method according to claim3 and comprising the additional steps of segregating a third portion ofsaid fluid adjacent said desiccant material, and periodically flowingsaid third fluid portion in a reverse direction along said path andthrough said desiccant material and said liquid separator to flushforeign material from said desiccant material and to aid in regeneratingsaid separator.
 6. The method according to claim 3 and comprising theadditional step of reverse-flowing said second portion at asubstantially faster rate.
 7. The method according the claim 6 andcomprising the additional steps of reverse-flowing said first and saidsecond fluid portions respectively to regions of substantially reducedfluid pressures.
 8. The method according the claim 3 and comprising theadditional step of segregating said first portion adjacent saiddesiccant and said second portion adjacent said separator.
 9. The methodaccording to claim 1 wherein at least two relatively thin foraminousliquid separators are spacedly mounted along said path and said methodcomprises the modified step of reverse-flowing said portion in tandemthrough said separators so that surface coalesced liquid on the normallyupstream separator is driven back through said upstream separator andthat the surface coalesced liquid on the normally downstream separatoris driven through both of said separators.
 10. The method according toclaim 9 and comprising the additional steps of segregating a secondfluid portion in a space between said separators, and periodicallyreverse-flowing said second portion through said upstream separator toaid at least partially in regenerating the same.
 11. A desiccant dryingsystem for use with a compressed fluid containing desiccantcontaminating liquid droplets, said system including a containerstructure for supporting a mass of desiccant material therein, aseparator for said liquid positioned within said container structure,means for spacing said separator in a normally upstream direction fromsaid desiccant material, said separator including a coalescing member ofthin foraminous construction and being extended entirely across the flowpath of said fluid through said desiccant, said member being shaped toretain substantially all of the coalesced liquid on the normallydownstream surface thereof, and means coupled to said containerstructure for periodically reverse-flowing a first portion of said fluidthrough said separator and for periodically reverse-flowing a secondportion of said fluid through said desiccant material for regeneratingsaid separator and said desiccant material respectively.
 12. Thecombination according to claim 11 wherein said liquid separator includesa relatively thin coalescing member and a pair of foraminous backingmembers coextending with said coalescing member and sandwiching saidcoalescing member therebetween.
 13. The combination according to claim12 wherein the liquid separator is positioned horizontally, said lowervolume flow is upwardly through said liquid separator, said highervolume flow is downwardly through said separator.
 14. The combinationaccording to claim 11 wherein at least two of said liquid separators arespacedly mounted in tandem in said system and along said path.